Cops have launched an all-out manhunt for the killer who gunned down a baby in his stroller, following leads from Brooklyn community organizers who say they know who pulled the trigger.

With a Brooklyn neighborhood up in arms over the latest senseless shooting and debate raging over the city’s stop-and-frisk policy, the death of 1-year-old Antiq Hennis left a shattered Brownsville in shock.

“We know exactly who the shooter is,” said Tony Herbert, a neighborhood activist. “It was a beef between the shooter’s brother and the baby’s father.”

Herbert said yesterday people in the neighborhood have come forward with a street name of the thug who shot Antiq in the head on a Brownsville street Sunday evening.

Herbert said there were ongoing negotiations to get the shooter to surrender.

Police sources said Antiq’s dad, Anthony Hennis, 21, who has an extensive arrest record, was the intended target, but cops said the grieving father was not cooperating with them.

“You would think he would want to see the killer of his own son brought to justice,” one cop said. “Luckily we do have some people who are trying to help us.”

The baby’s mom, Cherise Miller, stepped out of her home to thank supporters, but said nothing more.

Antiq’s grandfather, Floyd Hines, 77, said the tot loved his toy cars and his tricycle.

“He was a very nice little kid and he loved me to death,” Hines said. “All I can say is it’s very hard. He was a real joy. He always wanted to play.”

Shirley Jones-Baisley, vice president of Marcus Garvey Village where the baby lived, said she was heartbroken over Antiq’s death.

“I was at the hospital with them last night,” Jones-Baisley said. “We have babies that we have to raise and they die here early because we are not taking time out to understand what life has to offer us. I’m begging you, this is hard. I feel defeated right now.”

Cops are offering a $12,000 reward for information leading to the arrest and conviction of the boy’s killer.

Antiq’s death renewed the debate over the city’s controversial stop-and-frisk policy.

Angela James, 51, an accountant who has lived in Brownsville for 15 years, said she has mixed feelings about stop-and-frisk.

“I mean look what happened to that baby,” James said. “It’s ridiculous. But not every black person is a criminal. Some of us are professionals and we live in the neighborhood. I think they need to use a little more discretion when they stop people.”